bp_last_activity_migrate()

function bp_last_activity_migrate() {
	global $wpdb;

	$bp = buddypress();

	// Wipe out existing last_activity data in the activity table -
	// this helps to prevent duplicates when pulling from the usermeta
	// table.
	$wpdb->query( $wpdb->prepare( "DELETE FROM {$bp->members->table_name_last_activity} WHERE component = %s AND type = 'last_activity'", $bp->members->id ) );

	$sql = "INSERT INTO {$bp->members->table_name_last_activity} (`user_id`, `component`, `type`, `action`, `content`, `primary_link`, `item_id`, `date_recorded` ) (
		  SELECT user_id, '{$bp->members->id}' as component, 'last_activity' as type, '' as action, '' as content, '' as primary_link, 0 as item_id, meta_value AS date_recorded
		  FROM {$wpdb->usermeta}
		  WHERE
		    meta_key = 'last_activity'
	);";

	return $wpdb->query( $sql );
}